1. Field of the Application
The present application relates to an annular cover delimiting a lubrication chamber. More specifically, the present application relates to an annular cover delimiting a lubrication chamber of an axial turbomachine compressor. The present application also relates to a turbomachine having an annular lubrication chamber that is delimited on the upstream side by an annular cover.
2. Description of Related Art
The bearings of a longitudinal transmission shaft of an axial turbomachine are generally lubricated using an oil mist. This mist is contained within a sealed lubrication chamber, and the chamber is advantageously kept under negative pressure to prevent the oil leaking out. The chamber can be delimited on the upstream side by an annular cover that has ring seals. In particular, the annular cover may have two ring seals on the upstream side arranged in series about a shaft such as to form two consecutive sealing barriers in order to minimize losses.
The annular cover has an annular shape with a central opening on the upstream side and several pressurization channels distributed about the opening. The channels may be channels communicating with a compressor stage to pressurize the chamber directly.
According to other arrangements, the channels may be suction-driven oil recovery channels. These extend downstream from the upstream side to drain the oil into a lubrication circuit. For this purpose the turbomachine may include a suction system communicating with the channels. The channels generally open out downstream of the set of ring seals, and some channels can also open out between the ring seals such as to collect any oil that has passed through the seal directly in contact with the annular lubrication chamber.
Document FR 2 925 131 B1 discloses a sealing flange for a bearing lubrication chamber of an axial turbomachine. The flange is attached on the downstream side in the intermediate casing of the turbomachine and has two ring seals on the upstream side. The flange also has vents that are arranged between the seals and that extend radially. The vents are connected to pressurization pipes such as to pressurize the lubrication chamber through the seal on the downstream side. This arrangement makes it possible to pressurize a chamber and to reduce leaks. The flange thus formed has limited mechanical resistance and/or rigidity. Being installed in a turbomachine, it is subject to vibration. Under the effect of the inertia of same, the free upstream end thereof can oscillate and damage the seals assembled thereupon.
Although great strides have been made in the area of lubrication assemblies for turbomachines, many shortcomings remain.